polargraph_processing/libraries/geomerative/README

COPYRIGHT
---------------

Copyright 2006-2008 Ricard Marxer <email@ricardmarxer.com>

This product includes software developed by the Solution Engineering, Inc. (http://www.seisw.com/).

This product includes software developed by the The Apache Software Foundation (http://www.apache.org/).


INSTALL
---------------
Unzip the geomerative-XX.zip in the Processing libraries directory.
The result shoul look like this:
/path/to/processing/libraries/geomerative/library/geomerative.jar

USAGE
---------------
In the Processing IDE Sketch > Import Library > geomerative

DOCUMENTATION
---------------
The documentation is in the documentation folder.  Just open the index.html with any web browser.

MINI-TUTORIAL
---------------
This geometry library consists of three main classes:

RShape		- Contains subshapes formed of commands (move,lines,beziers,...)
RPolygon	- Contains contours formed of points
RMesh		- Contains strips formed of vertices

There are several uses of the library:

+ Draw shapes with holes, in order to do so, we create a new shape and add commands to it.  Once the shape is created we can:
	- draw it using draw(g) (note the use of g in order to draw the shape to the main PGraphics object)
	- convert it to a polygon using toPolygon()
	- acces its subshapes' commands or the points of these commands, accesing its attribute subshapes and the RSubshape methods

+ Draw polygons with holes, in order to do so, we create a new polygon and add points (addPoint(x,y)) or contours (addContour()) to it.  Once the polygon is created we can:
	- draw it using draw(g)
	- convert it to a mesh using toMesh()
	- acces its contours' points, accesing its attribute contours and the RContour methods
	- do binary operations over two polygons, using the methods diff(), union(), xor() and intersection()

EXAMPLE
--------------

/// Example to draw a simple shape with a hole
/// Converting the shape to a mesh in the setup() avoids having to tesselate it for each frame, therefore the use of RMesh
import geomerative.*;

RPolygon p;
RShape s;
RMesh m;
int t = 0;

void setup(){
  size(100,100,P3D);
  framerate(34);
  background(255);
  fill(0);
  //noFill();
  stroke(255,0,0);
  
  s = new RShape();
  
  s.addMoveTo(-30,250);
  s.addLineTo(30,150);
  s.addArcTo(50,75,100,30);
  s.addBezierTo(130,90,75,100,90,150);
  s.addLineTo(130,250);
  s.addBezierTo(80,200,70,200,-30,250);
  
  s.addMoveTo(60,120);
  s.addBezierTo(75,110,85,130,75,140);
  s.addBezierTo(70,150,65,140,60,120);
  
  p = s.toPolygon(100);
  m = p.toMesh();
}

void draw(){
  scale(0.25);
  translate(200,50);
  background(255);
  
  rotateY(PI/65*t);
  fill(0);
  m.draw(g);
  
  rotateY(PI/64*t);
  noFill();
  p.draw(g);
  t++;
}
/// End of example


/// Example calculating the difference of two polygons
/// Note the use of predefined polygons (createStar(), createCircle(), createRing(),...)
import geomerative.*;

RMesh m;
RPolygon p = RPolygon.createStar(120,70,6);
RPolygon p2 = RPolygon.createStar(60,50,30);

float t=0;

void setup(){
  size(400,400,P3D);
  framerate(24);
  //smooth();
  noStroke();
  fill(0);
  
  p=p.diff(p2);
  m = p.toMesh();
}

void draw(){ 
  background(255);
  translate(width/2,height/2);

  rotateX(t/39);
  m.draw(g);
  
  rotateY(-t/5);
  scale(0.3);
  m.draw(g);
  
  t++;
}
/// End of example



KNOWN ISSUES
-------------

- Under certain renderers there's a big loss of precision, resulting in really ugly renderings of fonts and polygons in general.
- When we decrease the font size we get bad results, bad shapes.  This must have to do with the font fixed point arithmetics, haven't studied any of that yet.